From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [RFC][PATCH 0/7] locking: qspinlock Date: Wed, 12 Mar 2014 07:15:03 +0100 Message-ID: <20140312061503.GH30956@twins.programming.kicks-ass.net> References: <20140310154236.038181843@infradead.org> <20140312023153.GW13647@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from merlin.infradead.org ([205.233.59.134]:47298 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752153AbaCLGPc (ORCPT ); Wed, 12 Mar 2014 02:15:32 -0400 Content-Disposition: inline In-Reply-To: <20140312023153.GW13647@dastard> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Dave Chinner Cc: Waiman Long , arnd@arndb.de, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, akpm@linux-foundation.org, walken@google.com, andi@firstfloor.org, riel@redhat.com, paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org, oleg@redhat.com On Wed, Mar 12, 2014 at 01:31:53PM +1100, Dave Chinner wrote: > With the queuing spinlock, I expected to see somewhat better > results, but I didn't at first. Turns out if you have any sort of > lock debugging turned on, then the code doesn't ever go into the > lock slow path and hence does not ever enter the "lock failed" slow > path where all the contention fixes are supposed to be. Yeah; its a 'feature' of the spinlock debugging to turn all spinlocks into test-and-set thingies. > Anyway, with all lock debugging turned off, the system hangs > the instant I start the multithreaded bulkstat workload. Even the > console is unrepsonsive. Oops, I only briefly tested this series in userspace and that seemed to work. I'll go prod at it. Thanks for having a look though. Is that bstat test any easier/faster to setup/run than the aim7 crap?